Project Soli, a Google initiative that uses minuscule radar to create virtual buttons, sliders and other interactions in thin air has been approved by US regulators.

The “disturbance sensor” haptics project has been in gestation since 2015.

It aims to enable touchless control of devices and is built around hardware that can be embedded in wearables, phones, computers, cars and IoT devices.

Project Soli: Why was Approval Needed?

The Federal Communications Commission (FCC) said in an order late Monday that it was providing a waiver for the project, which uses tiny radars to capture motion in a three-dimensional space. Concerns had initially been raised about interference with others services, including the Earth Exploration Satellite Service (EESS), which includes a frequency allocation for space-earth communications.

The FCC waiver will now allow Google to operate Soli sensors at higher power levels than currently allowed, as well as aboard aircraft, it said; albeit not as high levels as originally sought in its initial waiver request.

“We find that the Soli sensors, when operating under the waiver conditions specified herein, pose minimal potential of causing harmful interference to other spectrum users and uses of the 57-64 GHz frequency band, including for the earth exploration satellite service (EESS) and the radio astronomy service (RAS),” the FCC said.

“We further find that grant of the waiver will serve the public interest by providing for innovative device control features using touchless hand gesture technology”.

What is Project Soli?

To underpin Project Soli, Google owner Alphabet’s Advanced Technology and Projects (ATAP) group has built an entire sensor and antenna array into a single 8mm x 10mm solid state custom built chip. This includes a low-power radar operating in the 60-GHz ISM band.

Custom chip aside, the Soli software architecture is hardware agnostic, with a software development kit (SDK) that enables developers to access and build upon its gesture recognition pipeline already in the wild.

Soli extracts real-time signals from radar hardware, outputting signal transformations, high precision position and motion data, and gesture labels and parameters at frame rates from 100 to 10,000 frames per second, Google says of the project.

In its original waiver request, Google had sought a waiver of FCC rules to allow the short-range interactive motion sensing radar to operate in the 57-64 GHz frequency band. This would be at power levels consistent with European Telecommunications Standards Institute (ETSI) standard EN 305 550.

A public notice on March 12, 2018 by the FCC’s Office of Engineering and Technology (OET) soliciting comment drew concerns from third parties about interference with other services, including the EESS, however, and Google amended its waiver request.

“The current request indicates that an acceptable performance level can be achieved if Soli is permitted to operate at a peak transmitter conducted output power of +10 dBm (instead of -10 dBm as permitted in our rules), and at a peak EIRP level of +13 dBm
(instead of +10 dBm as permitted in our rules); as well as a peak power spectral density (PSD) level of +13 dBm/MHz. Google also states that it will limit the transmit duty cycle to 10 percent in any 33 millisecond interval,” the FCC noted.